Electrical clutch and brake.



A. l. 'STEGKEL & P. DU P. THOMSON.

ELEGTRIGAL CLUTCH AND BRAKE. APPLICATION FILED JULY 15, 1907.

912,504, i atented Feb. 16, 1909.

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776572 esss: 8a. 766

u AZZWrzqz A. P. STEOKEL & F. DU P. THOMSON. ELECTRICAL CLUTCH AND BRAKE. APPLICATION ITILED JULY 15, 1907.

91 2,504. Patented Feb. 1a, 1909.

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sen'tial.v to; the efiicient. 'operation. .of such UNITED STATES PATENT OFFICE.

ABRAM P. STECKEL, OF BUFFALO, NEW YORK, AND FRANCIS DU P. THOMSON, OF WHEELING, WEST VIRGINIA.

ELECTRICAL CLUTCH AND BRAKE.

Specification of Letters Patent.

Patented Feb. 16, 1909.

Application filed. July 15, 1907. Serial No. 383,797.

To all whom it may concern:

Be it known that we, ABRAM P. STEcKEL, a citizen of the United States, residing at Buifalo, in the county of Erie and State of New York, and FRANCIS DU P. THOMSON, a citizen of the United States, residing at Wheeling, in the county of Ohio and State of West Virginia, have invented a new and useful Improvement in Electrical Clutches and Brakes, of which the following is a specification. I

This invention relates to electrical induction clutches of the type disclosed in U. S. Letters Patent No. 744,423, dated November 17, 1903, in which two clutch members are emplo ed, one having electrically magnetized. poles and the other having a ring of conducting materia which. is a r nged; i cldseprpzgimity .tolsaid magnet. .olesinthe. magnetic..fieldTestitbliShad there y,

said ring by, induction tend to prevent any relative motion between the clutch members, or to cause the members to turn together. These clutches are desirable for transmitting motion, especially when it is required to -frequently start, stop. and reverse the driven member, and, they. are also useful as brakes, where one member is fixed, to. retard. or stop the motion. oftheothermember. It is es:

clutches that the conducting ring shall be close to the magnet poles to reduce the. air gap to. the minimum, but the parts become heated in action and, unless provision is made to prevent it, the expansion of the conducting ring is liable to Warp it so as to strike themagnet poles.

thereof; Fig; .3 is an elevation, on a reduced.

scale, .oflthe" driven member thereof; Fig. 4 isia sectional elevation of a modified conf structionof the clutch. 5 is a side elevation thereof. Fig. 6 is a fragmentary edge e e en 's; however;- ;Yei t on; and... a isuitable. wa mannerthatthe electrical currents ,set up in Q from the supply circuit.

view, )artly in section, on a reduced scale, thereo Fig. 7 is a sectional elevation of still another modification. Fig. 8 is a side elevation thereof. Fig. 9 is a diagrammatic sectional elevation indicating the paths or the currents in the conducting ring.

Like letters of reference refer to like parts in the several figures.

A represents the fast or driving member, and B the loose or driven member of the clutch. The former, in the clutches shown, is keyed on a driving shaft 0, While the latter is journaled to turn freely on said shaft and is provided with a gear wheel 0 for transmitting motion to the part to be driven thereby. The manner of mounting and connecting the. members to. the. driving and driven .f rri -.pa t..o t sila peei i he i any Onefof 'theclutcli,members, preferably the driving member A, consists of'a wheel or body provided around its peripheral portion with oppositely facing pole pieces separated by an intervening space or air gap, and the other member consists of a spider or body and a'ring of co per, or other good electrical -conductor, whic is arranged ina plane perpendicular to the axis of rotation thereof and in; the'zspace between. the op osite pole pieces of the. first member; :Eac member may be variously constructed.

1n the construction shown in Figs. 13, the pole pieces D extendv laterally toward each other fromopposite arms (1 projecting radially outward from a circular rim (1 of the supporting wheel or body. The pole pieces are .indivldually excited by separate sur- The principal objects of this invention are rounding coils d wound in such manner that the magnetic circuit is completed through each .pair of opposite pole pieces and the arms and rim of the supporting wheel or body, as indicated by the arrows in Fig. 1, the mag netic lines of force passing transversely through the rim d of the Wheel or body.

, The terminals of the magnet windings can be connected to collector rings d on the hub of the memberA to receive the electric current The conducting ring E is'secured to lateral extensions of radial arms e 'of ,the supporting spider orf-body,

' the connections being outwardly beyond the ring. The arms e are made-relatively wide and thin whereby they have therequisite strength to resist and transmit power in a ill) tangential direction, while their lateral extensions can yie.d or spring radially to allow for the expansion and contraction of the conducting ring withoutcausing it to warp so as to strike the pole pieces at the opposite sides thereof.

In the construction shown in Figs. 4-6, the magnet poles D are arranged between and connected to spaced circuiar iron rings or flanges d at the periphery of the supporting wheel or body. Magnetic circuits are completed through each two adj acentpairs of po .e pieces and the two rings, as indicated by the arrows in Fig. 6. In this construction the conducting ring E is a.'so secured outside of the member A to lateral extensions of the spider arms of the member B, but these arms are made rigid, and to allow for the expansion and contraction of the conducting ring it is attached to the spider arms by bolts f adapted to move radially in s.ots in said arms or by any other suitahe means allowing free expansion. This construction has an advantage over the other, in that the same weight of iron in the rings cl VVlil give a greater fly wheel effect on account of their greater distance from the axis of rotation.

In both of the constructions described the "magnet poles are individually excited and the conducting ring is connected outwardly beyond the same to its supporting wheel or body, but the pole pieces could be excited by a single coil winding encircing the body of the member carrying the pole pieces, and the conducting ring cou.d be connected to a supporting wheel or body inside thereof, as shown in Figs. 7 and 8, in which A is the driving member, B the driven member, D the pole pieces, E the conducting ring, and G the exciting winding. In this construction also the expansion and contraction of the conducting ring is allowed by bolts h passing therethrough and adapted to move iadlially in slots in the supporting wheel or or y.

The constructions shown in Figs. 1-6, in which the poles are individually excited, are better adapted for very large clutches, as a single large coil of wire would be bulky and unwieldy. Another advantage of the individual excitation of the poles is that it reduces the magnetic leakage which is inevitable when all of the poles are magnetized by one coil. The magnetic leakage consideration is, however, outweighed in clutches of small sizes by the more simple single coil construction. A single magnetizing coil could also be employed in the first two constructions in which the conducting ring is connected to its supporting member outside of the other member, and similarly the poles, in the construction shown in Figs..7-9, could be individual y excited.

The conducting ring E, Figs. 4-6, is composed of two outside copper rings with an inis reduced in thickness between its outer and inner edges opposite to the pole pieces D By thus forming the ring the air gap is not widened but the cross-sectional area of the ring is much larger, thereby greatly increasing its conductivity. In the use of this ring the induced currents flow through the thick inner and outer portions of the ring, as indicated by the arrow lines in Fig. 9, and will have a path of less resistance than they would have were the disk made of the same thickness throughout as that thickness best suited to be used in the space between poles. This conducting ring likewise could be used in clutches of the character shown in Figs. 1-6.

conducting ring. is arranged perpendicularly to its axis of rotation and is connected to the of, to prevent itfrom warping and striking the magnet poles. The fact that the part in which the induced currents are set up is in the form of a ring free to expand instead of a plate or disk rigidly connected centrally to a supporting shaft, and of necessarily unequal temperature in diiferent parts makes the expansion and contraction thereof more uniform throughout the area of the ring and lessens the tendency to warp or distort it.

The specific construction of the ring shown in Figs. 4-6 and of theclutch and ring shownin Figs. 7-9 are not claimed herein as they are the sole inventions of the applicants, Thomson and Steekel, respectively, and form the sub'ect matter of separate applications.

We claim as our invention:

1. An electrical induction clutch or brake comprising a member having. magnetized pole pieces, a second'member, and a conductmg ring supported thereby adjacent to said pole pieces 1n a plane perpendicular to the axis of said clutch, and connections between said ring and the supporting member which permit movement of said ring in the plane thereof relative to the supporting member to allow for the expansion and contraction. thereof, substantially as set forth. e

2. An electrical induction clutch or brake comprising a'mem'ber having oppositely facing magnetized pole pieces, a second member, and a conducting ring supported thereby between said pole pieces in a plane perpendicular to the axis of said clutch, and connections between said ring and the supporting mem- In all of the constructions illustrated the her which ermit movement of said ring in the plane t erect relative to the supporting member to allow for the ex ansion and eontraction thereof, substantia ly as set forth.

3. An electrical induction clutch or brake comprising a clutch member having opposite pole pieces, electrical windings for indlvidually exciting said pole pieces, a second clutch member, and a nonmagnetic conducting ring arranged between said pole pieces in a plane perpendicular to the axis of the clutch and connected to portions of said second clutch member located outwardly beyond said first clutch member, substantially as set forth.

4. An electrical induction clutch or brake comprising a member having oppositely arranged magnetized pole )ieces, a second member having arms with iateralextensions which are flexible radially, and a conducting ring supported by said arm extensions between sa d pole pieces in a plane )erpendicular to the axis of said clutch whereby said clutch ring is permitted movement in the plane thereof to allow for the expansion and contraction of the ring, substantially as set forth.

5. An electrical induction clutch or brake, comprisin a clutehmember having a body and spacer peripheral rings, pole pieces projecting, toward each other from said rings, electrical windings for individually exciting said pole pieces, a second clutch member, and a non-magnetic conducting, ring arranged between said pole pieces in a plane perpendicular to the axis of the clutch and connect ed to portions of said second clutch member located outwardly beyond said first clutch member, substantially as set forth.

Witness ourhands, this 27th day of June, 1907.

F. U P. "HOMSON.

Witnesses:

I. F. Jonas, H. S. BRADLEY. 

